An increasing trend in the semiconductor industry is to highly integrate an integrated circuit multiple times. For example, the semiconductor may include multiple generally independent functional units that perform the same function. Each functional unit has the same sub-functional units.
Referring now to FIG. 1, a semiconductor 8 includes M generally independent functional units 10-1, 10-2, . . . , and 10-M (collectively referred to as functional units 10) that perform the same high level function. Each functional unit 10 includes the same N sub-functional units. For example, the functional unit 10-1 includes sub-functional units 11, 21, 31, . . . , and N1. The functional unit 10-2 includes sub-functional units 12, 22, 32, . . . , and N2. The functional unit 10-M includes sub-functional units 1M, 2M, 3M, . . . , and NM. The sub-functional units in a row perform the same low level function. Typically, there are no connections between the functional units other than ground and power. There are, however, connections between the sub-functional units in a functional unit. The connections may be one-way or two-way and may include one or more connecting wires.
Referring now to FIG. 2, an exemplary functional unit may be a Gigabit physical layer device 70. For example, four or eight Gigabit physical layer devices may be fabricated on the semiconductor. The physical layer device 70 includes a first sub-functional unit 74 that performs physical coding sub-layer (PCS), Flow Control Token (FCT), and Decision Feedback Sequence Estimation (DFSE) functions. A second sub-functional unit 76 implements a finite impulse response (FIR) filter function. A third sub-functional unit 78 performs echo and near end crosstalk (NEXT) functions. Fourth and fifth sub-functional units 80 and 84 implement digital and analog front end (AFE) functions, respectively.
If the yield for each individual functional unit is 90%, then the yield for the semiconductor with x identical functional units is (0.9)x. For example, if a semiconductor includes eight functional units each having a yield of 90%, the yield of the semiconductor is 43%, which is not an acceptable yield.